Waterproof Mavic?

Mavic Pro Water Recovery

 How I fixed my Mavic Pro after it crashed into the water and waterproofed most of the electronics.

For well over a year I have been bringing my Mavic Pro out in my kayak. I get out on the water, pull it out of the dry bag, set it up attach the floats, and then launch from the water. When I’m done, I land it in the water next to me, swap batteries for another flight, or stick it back in the dry bag.
A few months ago, my wife and I decided to paddle the Dora Canal here in Central Florida.

There I was paddling along in my kayak with my Mavic Pro on floats following me with Active Track like I have done dozens of times before. I would paddle along, and if the drone got near a tree Obstacle Avoidance (OA) alarm would go off and I would stop paddling and reposition the Mavic away from the trees, then paddle some more. This time was different. I heard a crack and looked over my shoulder to see the drone tumble through some branches into the water.

I turned the kayak and was paddling to the drone as fast as I could while I watched the rear float bracket with floats slowly rotate from under the Mavic and float away. As the rear floats came out from under the Mavic, the rear of the drone sank into the water. When I got there, the Mavic was upside down under the water with its nose up floating by the front floats. Even with rear floats missing, the drone didn’t completely sink. I wish I would have thought to take a picture of it, but I was a bit freaked out and anxious to get in in the boat. I was thrilled it was not at the bottom of the canal. I pulled it out, removed the battery, and paddled back to the boat launch to load the kayaks and go home.

This article is about recovering my Mavic from its swim, but I have to say that when the next version of a Mavic Pro comes out, I hope it has rear OA sensors so I can have it active track backwards in front of me—and can keep a better eye on it. I have said from the beginning the sensors are on the wrong side of these drones. I would much rather have my face in the shot than the back of my head. That’s partly why I bought a Mavic Air. Although I wish the Mavic Air had a longer flight time.

On the way home, I stopped and picked up a couple pounds of dried rice. After wiping the drone off, I dumped the rice, the Mavic Pro, and the battery in a 5-gallon bucket, clipped the airtight lid on it, and let it set in my shed for a couple of weeks.
Before pulling the Mavic out of the bucket, I watched a couple videos on how to dismantle a Mavic Pro.
https://youtu.be/ndZVS8CtTLw
https://youtu.be/_4rfiX7JmOg
https://youtu.be/ydabCZ4bUd4
I have years and years of experience building and repairing RC aircraft. Planes, Helicopters, Multi-Rotors/Drones. If you’re not experienced with this, taking apart a Mavic Pro may not be something you should attempt.
I carefully dismantled my Mavic until I had access to all the circuit boards—making sure to keep the bolts separated in a way to help ensure the different lengths and types go back in the right places.

The rice had done its job. I didn’t find any moisture in the Mavic. To ensure there was no corrosion or moisture I might have missed, I cleaned all the boards with contact cleaner then brushed Corrosion-X on the boards and all connections.

I was careful not to get Corrosion-X on the positioning cameras, which I cleaned carefully before reassembly. The drone needs a clear view of the ground for good low-level hovering and landings. I also cleaned and checked to make sure I could see through the positioning camera lenses in the heat sink.

If you’re not an airplane mechanic or boat guy, you may not have heard of Corrosion-X. It is great stuff.
Besides dissipating moisture and corrosion, it can protect metal and electrical connections for years from moisture and corrosion making the Mavic Pro very water resistant nearly waterproof in case this happens again.
This video can give you an idea of just how effective Corrosion-X is:

Then I carefully put the drone back together making sure I put the correct screws on top, on the bottom, and the long-shouldered ones in the middle of the heat sink on the bottom.  I also added a little Thermal Compound Paste between the heat sink and chips to help ensure good heat transfer.

I installed all the bolts in for each section before tightening them to ensure proper alignment. Then I snugged them in steps using a cross pattern working from the middle out, being careful not to over-tighten them.

The battery that was on the Mavic when it went in the water never recovered. It will not charge.
After a through pre-flight I powered up the controller and the drone. Doubled checked everything and gave it a test flight. It did drift some, so I plugged it into the computer and calibrated the positioning cameras, then calibrated the IMUs, then of course the compass. My Mavic Pro flys great again. The camera works and everything! With the Corrosion-X treatment and my float kit, I feel much better about flying it over water in case it crashes again.

Quick note on my float kits. I have said from the beginning that they are designed for water operations, not crashing. They are designed to break before breaking the drone in a crash.
They will stay on and float the Mavic upside down if it is capsized, but if they hit something they may come off.
Just ask No Fish Nick, he uses my float kit for his fishing channel.

• Check out 0:58

• Check out 2:28

I hope you found this entertaining and maybe even learned something. More stories tips and tricks coming soon.
Fly safe.
Mike

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